Koo Phil-Joon, Lee Jong-Hyuk, Ha Seung-Ryong, Seo Deog-Gyu, Ahn Jin-Soo, Choi Yu-Sung
Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan 31116, Republic of Korea.
Department of Conservative Dentistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Republic of Korea.
J Funct Biomater. 2025 Mar 10;16(3):96. doi: 10.3390/jfb16030096.
This study assessed the changes in the mechanical and surface properties of the transition zone in multilayered translucent monolithic zirconia subjected to long-term hydrothermal aging. A total of 360 disk-shaped specimens (diameter: 15.0 mm; thickness: 1.2 mm) were prepared using conventional (3Y-TZP in LT; ZL, 4Y-TZP in MT; ZM) and multilayered translucent zirconia (5Y-TZP in MT Multi; ZT, 3Y/5Y-TZP in Prime; ZP) among IPS e.max ZirCAD blocks. Specimens were divided into three groups ( = 30) and aged in the autoclave at 134 °C under 0.2 MPa for 0 h (control group), 5 h (first aged group), and 10 h (second aged group). The mechanical and surface properties of the transition zone in the multilayered translucent zirconia were investigated, followed by statistical analysis (α = 0.05). Before and after aging, ZL (1102.64 ± 41.37 MPa) and ZP (1014.71 ± 139.86 MPa) showed the highest biaxial flexural strength (BFS); ZL showed the highest Weibull modulus (31.46) and characteristic strength (1121.63 MPa); and ZT exhibited the highest nanoindentation hardness (20.40 ± 1.80 GPa) and Young's modulus (284.90 ± 20.07 GPa). After aging, ZL (116.75 ± 9.80 nm) exhibited the highest surface roughness (); the monoclinic phase contents in ZL and ZP increased; and surface uplifts, microcracks, and irregular defects caused by phase transformation appeared on ZL and ZP surfaces. The 3Y/5Y-TZP transition zone exhibited flexural strength, Vickers hardness, phase distribution changes, and surface microstructure changes similar to those of 3Y-TZP before and after aging; however, the surface roughness was lower than that of 3Y-TZP and higher than those of 4Y-TZP and 5Y-TZP after aging. The mechanical and surface characteristics, excluding BFS and Vickers hardness, were influenced by the yttrium oxide content in each zone and the aging process.
本研究评估了多层半透明整体式氧化锆在长期水热老化后过渡区力学性能和表面性能的变化。使用IPS e.max ZirCAD块材中的传统材料（低温区的3Y-TZP；ZL，中温区的4Y-TZP；ZM）和多层半透明氧化锆（中温多层区的5Y-TZP；ZT，Prime中的3Y/5Y-TZP；ZP）制备了总共360个圆盘形试样（直径：15.0毫米；厚度：1.2毫米）。试样分为三组（每组n = 30），在高压釜中于134℃、0.2MPa条件下分别老化0小时（对照组）、5小时（第一老化组）和10小时（第二老化组）。研究了多层半透明氧化锆过渡区的力学性能和表面性能，随后进行统计分析（α = 0.05）。老化前后，ZL（1102.64±41.37MPa）和ZP（1014.71±139.86MPa）表现出最高的双轴弯曲强度（BFS）；ZL表现出最高的韦布尔模量（31.46）和特征强度（1121.63MPa）；ZT表现出最高的纳米压痕硬度（20.40±1.80GPa）和杨氏模量（284.90±20.07GPa）。老化后，ZL（116.75±9.80nm）表现出最高的表面粗糙度（）；ZL和ZP中的单斜相含量增加；ZL和ZP表面出现了由相变引起的表面隆起、微裂纹和不规则缺陷。3Y/5Y-TZP过渡区在老化前后表现出与3Y-TZP相似的弯曲强度、维氏硬度、相分布变化和表面微观结构变化；然而，老化后其表面粗糙度低于3Y-TZP，高于4Y-TZP和5Y-TZP。除BFS和维氏硬度外，力学性能和表面特性受各区域氧化钇含量和老化过程的影响。
